The present invention relates to a method for the preparation of a semiconductor device or, more particularly, to a high-yield method for the preparation of a semiconductor device of high reliability by decreasing the number of defects occurring in the process of photolithographic patterning of a photoresist layer.
As a trend in recent years, the requirement for a higher degree of integration in semiconductor devices is increasing year by year and mass production of LSIs having a fineness of the design rule of about 0.20 xcexcm has now left the starting point and the schedule for the mass production of LSIs having fineness of the design rule of about 0.15 xcexcm is rapidly approaching its starting point.
In connection with this trend toward greatly increased fineness of patterning in the manufacture of semiconductor devices, upgrading of the photoresist compositions, which are pattern-wise exposed to KrF excimer laser beams, is now required to comply with the 0.12 to 0.18 xcexcm fineness of patterning for line-and-space patterns, hole patterns and isolated patterns.
Along with the above mentioned trend toward increased fineness of patterning of photoresist layers, on the other hand, another important problem to be solved is the number of defects occurring in the patterned resist layer after development, which was not taken as so serious heretofore. Namely, high-yield mass production of semiconductor devices having high electric reliability can be accomplished only by greatly decreasing the number of defects occurring in the photoresist layer.
The defects here implied include any of the defects found in the patterned resist layer such as adherence of scums, disordered patterning of the resist layer and others, which can be detected by inspecting the patterned resist layer after development just from above on a surface-defect inspection instrument such as the instrument Model KLA manufactured by KLA Tencole Co.
Under the above described circumstances, the present invention has an object to provide a method for the production of semiconductor devices of high electrical reliability in a high yield by greatly suppressing occurrence of defects in the patterned resist layer which was not taken as so serious heretofore from the standpoint of quality control.
Thus, the present invention provides an improvement in a method for the preparation of a semiconductor device by forming a patterned resist layer on the surface of a substrate by pattern-wise light-exposure of a photoresist layer of a chemical-amplification positive-working photoresist composition comprising (A) a compound capable of generating an acid by irradiation with actinic rays and (B) a resinous compound capable of being imparted with increased solubility in an aqueous alkaline solution in the presence of an acid, which improvement comprises decreasing the number of defects in the patterned resist layer by selecting the photoresist composition of which the photoresist layer before the pattern-wise light-exposure exhibits reduction of thickness at 23xc2x0 C. in an aqueous alkaline solution at a rate in the range from 0.09 to 1.0 nm/second.